U.S. Pat. No. 4,601,159 discloses the technology where a longitudinally moving tube film is perpendicularly nipped by a pair of seal bars, and immediately before the respective materials to be packaged in the tube film are isolated and sealed, the tube film is cut by cutting edges incorporated in the seal bars, and the air in the tube film is removed through the cut portion to form a continuous vacuum packaged body.
The details of technology disclosed in the above specification are such that the tube film is cut between the front and rear materials to be packaged, the cut end parts are sucked to the dome-like wall inner surface to be largely opened, and the air in the tube film is removed from the opening parts. The positive opening of the cut end part is intended for heightening the efficiency of removing the air in the tube film, but unsuppressed opening for the tube film in the apparatus has high possibility of causing distortion at the open end part, so that even if the open edge is sealed by heat, the above distortion impairs air tightness of the sealed part to exert bad influence upon the sealing performance of the vacuum packaged body. Consequently, the above apparatus is adapted to cut a film opening part and remove the same, and heat-seal two new opposite cut ends of both sides of the removed part, resulting in the disadvantage of causing lowering of efficiency due to the waste of a film in cutting and removing the film and the complicatedness of operation process.